The invention relates to an ultrasound welding process and an ultrasound welding device, and to a welding connection produced therewith.
In rotating electrical machines, such as starter drive motors for motor vehicles, it is known to insert commutators as connecting elements between rotating coils (armature winding) and the unmoving supply leads for them. To that end, the commutators have laminations insulated from one another that have contact regions, at which the beginning of one coil and the end of another coil of the armature winding are connected in accordance with the anchor wiring chosen. Thus at each contact region, there are two wire ends of the armature winding to be secured. To that end, it is known to secure the wire ends lying one above the other to the contact regions by means of a resistance diffusion welding process. To that end, one welding electrode of a welding device is connected to the commutator, and the other welding electrode is extended from outside to the outer wire end. A flow of electrical current then effects welding of the wire ends to one another and of the lower wire end to the contact region. A disadvantage here is that the wire ends require special preparation to enable them to be used for the resistance diffusion welding. As a rule, the wire ends are tin-plated for that purpose. Another disadvantage is that each lamination has to be electrically contacted individually, making it relatively time-consuming to secure all the wire ends to the commutator.